There were lots of times during our separation when I was barely functional. It was hard to pray, hard to worship, hard to do anything. In 2 Corinithians 4:10, Paul says, "The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds."
Often when I couldn't get anything else out, I would pray the Lord's Prayer. I often prayed through Psalm 51, which was David's prayer after his affair with Bathsheba. Even if we haven't sinned in the same manner as he, who of us couldn't use a clean heart and joy in salvation, especially if we are separated?
For me, speaking Psalm 23 out loud gave me alot of comfort.
I think Beth Moore said once that when she gets in that awful place where just nothing will come out of her mouth, she speaks the name of Jesus, and shortly she will have a release and then maybe she can speak scriptures.
Kenneth Copeland said something similar. "When you speak out the name of Jesus it is like throwing the whole Bible in Satan's face."
Lots of times I just put on worship. Twila Paris and John Elliott were two artists whose worship ministered deeply to me even when all I had the strength to do was hit "play".
I did this on those days when it just seemed like I didn't have energy for anything else.